the auxiliary cooling fan on my 98 e320 doesn't work properly.i've replaced the fan control module but the fan doesn't come on high. if i disconnect the fan and measure voltage i have over 12 volts when the engine is hot and ac on but when i plug the fan in the fan comes on high speed for a couple of seconds then spins at low speed.the voltage plugged in drops to less than 4 volts.i tried another fan and it does the same.with my original fan control module the voltage was fluctuating from around 2 volts to above 13 volts then stopped working all together.i'm a gm tech and i took it to mercedes dealer and a kind fellow team leader tech checked my car out and concluded that the S.A.M. (signal acquiring activation module) was the problem.i put one in before i changed the fan control module and it didn't work, that's when i changed the fan module but still have problem can anyone help?